1– The Prophet (SAWA) said, 'O Ibn Mas`aud, beware of ever associating anything with Allah for even the twinkling of an eye, even if you are to be cut up with a saw, amputated, crucified or burnt with fire.’
[Makarim al-Akhlaq, v. 2, p. 357, no. 2660]

الشِّرك

POLYTHEISM

3– Imam al-Baqir (AS) was once asked what the absolute minimum of polytheism was, to which he replied, 'It is to call fruit kernels stones and vice versa, and to believe them as such.’
[al-Kafi, p. 397, no. 1]

4– Imam al-Sadiq (AS) was once asked what the absolute minimum of polytheism was, to which he replied, 'It is to contrive a ruling and falsely cause people to take sides for and against it.’
[al-Kafi, no. 2]

6– Imam al-Sadiq (AS) said when interpreting the Qur’anic verse: “And most of them do not believe in Allah without ascribing partners to Him”, ‘This is in reference to man’s statement: “Were it not for ‘x’ I would surely have perished”, or “Were it not for ‘x’ I would indeed have been afflicted” or “Were it not for ‘x’ my family would be at a loss.” Do you not see that he has associated a partner to Allah in His Kingdom giving him sustenance and repelling misfortune from him?’ He was subsequently asked, ‘What if one were to say, “Were it not for Allah granting me x’s help, I would have perished…?” Imam replied, 'There is nothing wrong with saying things like this.’
[Tafsir al-`Aayyashi, v. 2, p. 200, no. 96]

7– Imam al-Sadiq (AS) said when interpreting the Qur’anic verse: “And most of them do not believe in Allah without ascribing partners to Him”, ‘This refers to ascribing partners in Allah's obedience, not
[just] in His worship.’
[al-Kafi, v. 2, p. 397, no. 4]

8– Imam al-Sadiq (AS) said, 'Polytheism is more discreet than the crawling of an ant, and includes things like turning one's ring to make a wish, and other such
[superstitions].’
[Ma`ani al-Akhbar, p. 379, no. 1]

9– Imam al-Sadiq (AS) said when interpreting the Qur’anic verse: “And most of them do not believe in Allah without ascribing partners to Him”, ‘This refers to when people used to say, 'We are being rained on from the storm of x, or the storm of y
[referring to various false gods]. And they used to consult soothsayers and believe whatever they told them.’
[Bihar al-Anwar, v. 58, p. 317, no. 8]

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Translator's Note: The word shirk in Arabic implies a much wider meaning that the English 'polytheism' which has been defined as: worshipping or believing in more than one deity, idolatry. In Islam, its purport, in addition to ascribing partners to Allah, includes any form of association of anything or anyone with Allah's authority, His worship, His Names, His attributes, and His Greatness. This includes, therefore, vices such as self-worth, pride, showing-off, etc… Shirk has been translated in the text as polytheism for ease of translation.